高レベル放射性廃棄物地層処分における地下水・熱水―岩石相互作用の重要性

抄録

Hydrothermal solution scenario and uplift-erosion scenario are important for high level nuclear waste disposal in Japan.The study on the rare earth elements behavior in the hydrothermal alteration in the Kuroko deposits suggests light rare earth elements did not release during the hydrothermal alteration of volcanic glass which could be a chemical analogue of Am and Cm derived from high level nuclear waste glass.
The study on the weathering of soils (andosol, red-yellow soil) indicates that the secondary minerals (iron hydroxides, manganese oxide, clay minerals) retard the migration of rare earth elements by the adsorption and ion exchange reaction. This suggests that radioactive elements (e.g., Am, Cm) in shallow geologic environments are retarded by these mechanisms.